Place the car seat on a flat surface or keep it installed in the vehicle
Locate the harness adjuster strap at the front of the seat
Press and hold the harness release button or lever
Pull the shoulder straps outward from the front of the seat to loosen them
If needed, lift the harness adjuster flap or cover to access the straps
Make sure both straps loosen evenly
Check that the harness is not twisted
Reposition the child and re-tighten the straps as needed